Electrosurgical instrument with minimally invasive jaws

ABSTRACT

A surgical instrument useful in harvesting blood vessels such as veins and arteries and for manipulating and grasping tissue. The instrument has a pair of jaws and a closing tube to open and close the jaws.

FIELD OF THE INVENTION

[0001] The present invention relates, in general, to bipolarelectrosurgical instruments and, more particularly, to bipolarelectrosurgical instruments incorporating offset electrodes.

BACKGROUND OF THE INVENTION

[0002] Surgeons and surgical assistants have been using medical devicesincorporating radio frequency (RF) electricity for many years tocauterize and coagulate bodily tissues during surgical procedures. Twotypes of RF surgical devices are conventionally utilized: mono-polar andbipolar. Both incorporate a pair of conductors for transmission ofalternating RF electricity. In a mono-polar electrosurgical instrument,a first conducting electrode having a first polarity is typically placedon the patient's skin and communicates through the body, i.e. forms aconductive path, with a second conducting electrode having the oppositepolarity located on the surgical instrument. A bipolar electrosurgicalinstrument, however, typically incorporates both first and secondelectrodes of opposite polarity in the same surgical instrument,substantially restricting the flow path of electric current to tissuethat is contained between the electrodes. As mentioned previously, bothmono-polar and bipolar electrosurgical instruments apply RF energythrough tissue. The energy is dissipated within the tissue in the formof heat due to the natural impedance of tissue. As the temperature ofthe tissue rises, the electrical resistivity of the tissue increases.When RF energy is applied to tissue, and as the temperature reachesabout 67-70 degrees Celsius, the tissue begins to coagulate. Asincreasing amounts of energy dissipate in the tissue, the collagenforming the tissue matrix breaks down and appears to “melt”. Mechanicalcompression of the coagulating tissue layers fuses and seals anycontained blood vessels, so that the tissue may be cut without bleeding.When the tissue temperature reaches 100 degrees C., most fluids(including water) vaporize into the surrounding tissues and air.

[0003] The energy dissipation rate in tissue depends on numerousfactors, including the inherent electrical resistivity of the tissue andthe electrical current density. Electrical current density in varioustissues is an important consideration in the design of the electrodes ina bipolar electrosurgical instrument, including the number, size, shape,and placement of the electrodes.

[0004] Many surgeons prefer to use bipolar electrosurgical instrumentsfor hemostatically (without bleeding) sealing tissue prior totransection. Bipolar electrosurgical devices are known for grasping,coagulating, and cutting tissue. Typically the instruments have graspingelements, and one of the grasping elements is an electrically oppositepole of the other grasping element. For this type of conventional,bipolar electrical configuration, electrical current can besimplistically thought of as “flowing” from one grasping element (apositive pole), through the grasped tissue, and to the other graspingelement (a negative pole). When tissue held between the graspingelements is coagulated, it is known that the electrical resistivity ofthat portion or zone of tissue increases dramatically. This causes theelectrical current to seek a new path of lesser electrical resistivityaround the zone, resulting in a spread to tissue adjacent to the outsideof the grasping elements. Accordingly, it is believed that the zone ofcoagulated tissue continues to increase laterally from the graspingelements. The final width of the coagulation zone depends on severalfactors, including the power setting of the electrosurgical generator,and on the length of time the operator applied electrical energy to thetissue, etc. It is typical for an operator to apply electrical energy(usually by stepping on a foot actuator) for several seconds more thanis actually needed to ensure that the grasped tissue is completelycoagulated prior to cutting to prevent bleeding. If the amount of tissuegrasped is very small, coagulation of the grasped tissue may occur soquickly that the operator cannot stop the application of electricalenergy quickly enough to prevent excessive lateral spreading of thecoagulation zone. In addition, the operator may not always be able tovisualize the spreading of the coagulation zone because of obstructingtissue structures, especially during an endoscopic procedure; or,because the coagulation of the tissue occurs on the inside of the tissueor blood vessel.

[0005] Excessive lateral spread of the coagulation zone may be harmfulto patients undergoing surgical procedures in which an organ or vesselis harvested for use in the same or a different patient. For example, ina coronary artery bypass graft (CABG) procedure, a surgeon or surgicalassistant may remove a saphenous vein from one of the patient's legs touse as one or more bypass grafts on that patient's heart. In recentyears, new surgical dissecting/retracting tools have been introduced toenable the surgical operator to harvest the saphenous veinendoscopically. Examples of endoscopic vessel harvesting devices andmethods are contained in the following U.S. Patents, which areincorporated by reference: U.S. Pat. Nos. 5,667,480; 5,722,934;5,928,135; and 5,928,138. In such surgical procedures the operator“tunnels” with the surgical dissecting/retracting tool alongside thevein under the skin, working through a small incision made into theinside of the patient's leg or knee. The benefits of this procedure tothe patient are numerous because endoscopic vein harvesting (EVH)results in greatly reduced recovery time and pain for the patient ascompared to the earlier open procedure of creating an incision along theleg equal to the length of the vein harvested. In addition scarring islimited, and the incidence of serious infections reduced.

[0006] In conventional EVH procedures, the surgical operator uses thesurgical dissecting/retracting tool to create a small working space atthe distal end of the tool and adjacent to the vein being harvested. Asthe operator maneuvers the tool along the vein to separate the vein fromadjacent tissues, the operator typically encounters numerous smallercollateral vascular side branches of the main vein (usually about 15).To harvest the main vein with minimal bleeding of surrounding tissues,the operator may apply at least two conventional surgical clips to eachside branch encountered, using a conventional mechanical endoscopicsurgical clip applier. Then the clip applier is removed, an endoscopicscissors is inserted to cut the side branch between the applied clips.Each instrument insertion and removal is not only time-consuming, butcare must be taken not to cause trauma to the vein being harvested andto surrounding tissues in the leg. The operator may also use bipolarelectrosurgical scissors in place of mechanical clip appliers, which arewell known in the art for use in this type of surgical procedure.However, bipolar scissors may induce undesirable lateral spreading ofthe coagulation zone if not used correctly, and the experience of theoperator is crucial in preventing injury to a harvested vein to be usedin the CABG procedure. When using bipolar scissors or any of the otherconventional electrosurgical instruments during an EVH procedure, theoperator is required to treat each side branch at a location as fardistant laterally from the main vein as practical, and the operator mustapply RF energy for a minimal time to seal the side branch for cutting.

[0007] Various embodiments of a relatively new kind of bipolar,electrosurgical device are disclosed in the following patentshereinafter referred to collectively as the “offset electrode device”,and are incorporated by reference herein: U.S. Pat. No. 5,403,312; U.S.Pat. No. 5,709,680; and U.S. Pat. No. 5,833,690. In the offset electrodedevice, the bipolar electrodes have an “offset” configuration andcoagulation of tissue is substantially confined to only the tissue heldbetween a pair of interfacing surfaces. The offset electrode devicesalso provide for high tissue compression to coagulate tissue uniformlyand to force fluid out of the coagulation zone. Such fluid wouldvaporize during coagulation and shoot laterally from the interfacingsurfaces, possibly causing thermal injury to adjoining tissue. Theoffset electrode devices disclosed, however, in the referenced patentsare not specifically adapted for use in endoscopic vein harvestprocedures or in other types of minimally invasive surgical proceduresrequiring 5 mm diameter endoscopic ports. There is a need in this artfor a bipolar electrosurgical instrument that may be used through a fivemillimeter trocar port, and that has minimally sized jaws for improvedaccess and visualization of tissue structures in the surgical site.

[0008] Another concern of the surgical operator when using anyelectrosurgical instrument is the tendency of coagulated tissue to stickto the jaws of the instrument during operation of the instrument. Theoperator must take additional time to manipulate the instrument torelease tissue adhering to the end effectors, possibly injuringsurrounding tissue, especially when operating in limited working spacesduring endoscopic procedures. Adhering tissue also reduces theelectrical conductivity of the bipolar electrodes and it is oftennecessary for the operator to manually clean the electrodes in order tocontinue using the instrument. This is especially prevalent forforceps-type grasping instruments incorporating the conventional bipolarelectrode (non-offset) configuration.

[0009] Many conventional surgical instruments incorporate cutting bladesfor transecting tissue held within the jaws. A potential difficulty withcutting blades of such instruments is “tissue-tagging” when the bladedoes not completely cut through all the tissue held in the jaws. Thismay occur, for example, if the cutting edge of the blade is dull ornicked. Another reason tissue-tagging may occur, or even some bleedingafter the tissue is coagulated and cut, is that the tissue is not heldfirmly enough within the jaws of the instrument as the cutting blade ispassed through the tissue held. When tissue is initially clamped withinthe jaws of the instrument, the clamping force may be very high due tothe elasticity of the fluid-containing tissue. But after the tissue hasbeen compressed for a period of time, and then is coagulated, most ofthe fluid has been driven out of the tissue, with the result that theelasticity of the tissue is greatly reduced. The clamping force on thetissue is also decreased so that the tissue may shift within the jaws asa cutting blade is passed through it. This presents the possibility thatnot all the tissue will be cut, or the cutting blade will pass through aportion of tissue that is not fully coagulated.

[0010] During some surgical procedures, including the EVH procedure, thesurgical operator must cut and dissect a first tissue structure awayfrom a second tissue structure prior to performing a transection orother surgical procedure on the second tissue structure. A conventionaltechnique for this type of surgical cutting and dissecting used a pairof conventional, mechanical scissors held in an open configuration, thusforming a vee-shape with the scissors blades. The scissors blades arethen advanced between the first and second tissue structures to cut andseparate them. At this point, the surgical operator may remove thescissors and continue the surgical procedure with another surgicalinstrument such as a clip applier for ligation of the second tissuestructure. During an EVH procedure, the exchange of endoscopicmechanical scissors and the clip applier in and out of the working spacemay occur many times, increasing the time to perform the procedure, andpossibly injuring the vein or surrounding tissue. An alternative tousing a mechanical scissors together with a clip applier is to use abipolar electrosurgical scissors as described previously. Usingconventional bipolar coagulation and cutting devices may result inexcessive lateral spreading of the thermally affected zone of tissue,especially if the operator is inexperienced or otherwise not careful.

[0011] Another shortcoming when using currently availableelectrosurgical cutting instruments with cutting blades is that thecutting blade may be exposed accidentally to adjacent tissue when theoperator does not intend to cut the tissue.

[0012] Accordingly, what is needed in this art is a bipolarelectrosurgical instrument incorporating offset electrodes andcompression zones, as described for the offset electrode device, yetimproved to be less surgically invasive and to provide better access andvisualization at the surgical site. There is also a need for a bipolarelectrosurgical instrument that easily releases tissue from the jawsafter each cycle of use, and automatically wipes electrode surfacesclean for each cycle of use. Additionally, there is a need for aninstrument having more than one cutting blade that cuts through thetissue held within the jaws to improve the probability of completelytransecting the tissue held, but without increasing the size or cost ofthe instrument. There is also a need for an instrument that provides foradditional clamping force to be applied to tissue held in the jawsimmediately prior to passing a cutting blade through the tissue. Thereis yet a further need for an instrument that safely coagulates tissuewithout excessive lateral thermal spread, and which reduces the need forusing mechanical scissors and clip appliers during a surgical procedure.Replacing a scissors and a clip applier with a single bipolarelectrosurgical cutting instrument, for example, and reducing surgerytime by reducing the number of instrument exchanges during the surgicalprocedure, allows a significant cost savings to the hospital, and isbeneficial to the patient. There is also a need for an electrosurgicalinstrument with a cutting blade that has an operational sequencingelement that allows the movement of the cutting blade through a tissuegrasping region only when the jaws are fully closed, thus reducing thepossibility of accidentally injuring the patient.

SUMMARY OF THE INVENTION

[0013] Therefore, it is an object of the present invention to provide abipolar electrosurgical instrument incorporating offset electrodes andcompression zones, that is less surgically invasive and that providesbetter access and visualization at the surgical site.

[0014] It is another object of the present invention to provide abipolar electrosurgical instrument that easily releases tissue from thejaws after each cycle of use, and automatically wipes electrode surfacesclean for each cycle of use.

[0015] It is yet another object of the present invention to provide aninstrument having more than one cutting blade that cuts through thetissue held within the jaws to improve the probability of completelytransecting the tissue held, but without increasing the size or cost ofthe instrument.

[0016] It is still yet another object of the present invention toprovide an instrument that provides for additional clamping force to beapplied to tissue held in the jaws immediately prior to passing acutting blade through the tissue.

[0017] Yet another object of the present invention is to provide aninstrument that safely coagulates tissue without excessive lateralthermal spread, and which reduces the need for using mechanical scissorsand clip appliers during a surgical procedure.

[0018] Still another object of the present invention is to provide anelectrosurgical instrument with a cutting blade that has an operationalsequencing element that allows the movement of the cutting blade througha tissue grasping region only when the jaws are fully closed, thusreducing the possibility of accidentally injuring the patient.

[0019] Accordingly, a surgical instrument is disclosed. The instrumenthas a handle having a proximal end, a distal end, a top and a bottom.There is a shaft having a distal end, a proximal end, and a longitudinalaxis. The proximal end of the shaft is mounted to the distal end of thehandle. A closing tube having a distal end, a proximal end, and alongitudinal axis is slidably mounted coaxially to the shaft. A firstjaw extends from the distal end of the closing tube. The first jaw has adistal end, a proximal end, and a longitudinal axis. The first jaw alsohas a hinge between the distal and proximal ends of the first jaw,wherein the distal end is rotatable or moveable about the hinge towardand away from the longitudinal axis of the first jaw A second opposedjaw extends from the distal end of the closing tube. The second jaw ismounted to the distal end of the shaft and retains the first jaw insideof distal end of the closing tube. The second jaw has a distal end, aproximal end, and a longitudinal axis. The closing tube slideably fitsover the first and second jaws so that a tissue grasping region of andbetween the first and second jaws is distal to the distal end of theclosing tube. The closing tube is movable relative to the first andsecond jaws between an open and a closed position. A cam is located onthe second jaw and operationally engaged with a follower member on thefirst jaw, such that when the closing tube moves from the closedposition to the open position the closing tube operationally engages thefirst jaw and moves the first jaw relative to the lower jaw in theproximal direction so that the follower member of the first jaw rides upon the cam on the lower jaw and causes the hinge to flex and the distalend of the first jaw to move away from the second jaw. When the closingtube moves from the open position to the closed position the closingtube operationally engages the first jaw and moves the first jawrelative to the second jaw in the distal direction so that the followermember rides down on the cam on the second jaw and causes the hinge toflex and the distal end of the first jaw to move towards the second jaw.An actuator is mounted to the handle for moving the closing tube and theproximal end of the closing tube is mounted to the actuator.

[0020] Yet another aspect of the present invention is a method of usingthe above-described surgical instrument to grasp or manipulate tissue.

[0021] The foregoing and other features and advantages of the presentinvention will become more apparent from the following description andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is an isometric view of an electrosurgical clamping,coagulating, and cutting instrument of the present invention shownconnected to a schematic of an electrosurgical energy generator.

[0023]FIG. 2 is an isometric view of the distal section of a tubeassembly of the instrument of FIG. 1, shown with an upper jaw in an openposition.

[0024]FIG. 3 is an isometric view of the distal section of the tubeassembly of the instrument of FIG. 1, shown with the upper jaw in aclosed position.

[0025]FIG. 4 is an exploded, isometric view of the distal section of thetube assembly of the instrument of FIG. 1.

[0026]FIG. 5 is a cross-sectional view of the distal portion of the tubeassembly taken through View-Line 5-5 of FIG. 3.

[0027]FIG. 6 is an exploded, isometric view of a handle assembly of theinstrument of the present invention.

[0028]FIG. 7 is a side view of the interior of the handle assembly ofthe instrument of the present invention with the left handle shellremoved, illustrating the actuators in positions to maintain the upperjaw in an open position and the cutting element in a central position.

[0029]FIG. 8 is a top view of the handle assembly of FIG. 7, with theleft and right handle shell assembled.

[0030]FIG. 9 is a longitudinal, sectional view of the distal section ofthe tube assembly of FIG. 7.

[0031]FIG. 10 is a side view of the handle assembly of the instrument ofthe present invention with the left handle shell removed, illustratingthe actuator positioned such that the upper jaw is in a closed positionand the cutting element is in a central position.

[0032]FIG. 11 is a top view of the handle assembly of FIG. 10 with theleft handle shell assembled with the right handle shell.

[0033]FIG. 12 is a longitudinal, sectional view of the distal section ofthe tube assembly of the instrument of FIG. 10.

[0034]FIG. 13 is a side view of the handle assembly of an instrument ofthe present invention having the left handle shell removed, showing theactuators located to cause the upper jaw to be in the closed positionand the cutting element in a proximal position.

[0035]FIG. 14 is a top view of the handle assembly of FIG. 13, with theleft handle shell assembled.

[0036]FIG. 15 is a longitudinal, sectional view of the distal portion ofthe tube assembly of the instrument of FIG. 13.

[0037]FIG. 16 is a side view of the handle assembly of the instrument ofthe present invention having the left handle shell removed, showing theacutators located such that the upper jaw is the closed position and thecutting element in a distal position.

[0038]FIG. 17 is a top view of the handle assembly of FIG. 16, with theleft handle shell assembled.

[0039]FIG. 18 is a longitudinal, sectional view of the distal portion ofthe tube assembly of the instrument of FIG. 16.

[0040]FIG. 19 is an isometric view illustrating the instrument of thepresent invention being used in combination with an endoscopic surgicalretractor for surgically harvesting a vessel from a patient.

BEST MODE FOR CARRYING OUT THE INVENTION

[0041] The electrosurgical clamping, coagulating, and cutting instrumentof the present invention is illustrated in FIG. 1 shown with a schematicrepresentation of an electrosurgical energy generator 6. Instrument 8 isseen to have a handle assembly 100 and a tube assembly 10 having adistal end section and a proximal end. Handle assembly 100 is seen to bemounted to the proximal end of tube 10. Handle assembly 100 furthercomprises a first actuator 104, a second actuator 102, and a power cord106 for electrical connection to electrosurgical energy generator 6. Anoperator actuates first actuator 104 for grasping and compressingtissue. The operator actuates second actuator 102 for cutting tissue.The operator presses a conventional foot switch (not shown) providedwith electrosurgical generator 6 for supplying bipolar electrosurgicalenergy to instrument 8.

[0042] Instrument 8 operates with numerous conventional, commerciallyavailable, electrosurgical energy generators. An example ofelectrosurgical energy generator 6 is a unitary mono-polar-bipolar RFgenerator, such as the Valleylab “FORCE 2” RF Generator manufactured byValleylab, a division of Tyco Healthcare Group LP, 5920 Longbow Drive,Boulder, Colo., 80301-3299, U.S.A.

[0043] Conventional power cord 106 may be long (for example, over twometers) and connect directly to electrosurgical energy generator 6 viastandardized, bipolar connectors, which are well-known in the art. Powercord 106 may also be short (less than one third of a meter, for example)and have a standardized, conventional bipolar connection (alsowell-known in the art) to another, longer power cord, which is normallyreusable and available with electrosurgical energy generator 6. Anoperator uses a foot-activated switch of electrosurgical energygenerator 6 to supply energy through instrument 8 to the tissue beingtreated. The operator adjusts the maximum power setting onelectrosurgical energy generator 6 to be in sufficiently effectiverange; for example a preferable range of approximately 20-60 watts,although instrument 8 operates at other conventional power settingsalso. The operator may press the foot switch and supply energy toinstrument 8 for a few seconds to coagulate the tissue being treated.Only a portion (about 3 watts) of this energy is conducted through thetissue due to the high resistivity of tissue and the use of offsetelectrodes as described earlier and hereinafter. The operator may useinstrument 8 to hemostatically seal a small (2-4 mm diameter) bloodvessel, for example, in less than one second, but the operator maycontinue to depress the foot switch a few more seconds if desired sincethere is believed to be practically no additional, lateral spreading ofthermal energy.

[0044] Referring now to FIG. 2, an isometric view of the distal portionor section of tube assembly 10 of FIG. 1 is illustrated. An elongated,closing tube 14 is shown retracted to an open position, holding upperjaw 42 in an open position relative to a stationary, opposing, lower jaw44. Upper jaw 42 and lower jaw 44 are preferably injection molded from abiocompatible plastic such as polycarbonate or polyethylene or otherconventional biocompatible polymeric materials. Closing tube 14 ispreferably made from a stainless steel tube, although other conventionalbiocompatible materials may be used. The operator moves closing tube 14in the proximal direction with respect to handle assembly 100 to openupper jaw 42 by moving first actuator 104 (see FIG. 1) in the proximaldirection. The operator moves closing tube 14 in the distal direction toclose upper jaw 42 by moving first actuator 104 in the distal direction.

[0045] Referring to FIGS. 2 and 3, closing tube 14 is shown to comprisea distal portion or section 18 and a proximal portion or section 16.Distal portion 18 of closing tube 14 is seen to have, preferably, anapproximately rectangular, cross-sectional shape with a left surface 20,a right surface 21 (hidden), an upper surface 22, and a lower surface 23(hidden), with surfaces 22 and 23 being curved as shown. Tube 14 mayhave other geometric cross-sections such as circular, polygonal, oval,square and combinations thereof. Distal portion 18 of closing tube 14further comprises distally extending upper arm 30 and lower arm 28separated by a left slot 32 on left surface 20, and an identicallyshaped right slot 33 (hidden) on the right surface 21 (hidden). Proximalportion 16 of closing tube 14 slides freely inside of an elongated,tubular sleeve 12. Closing tube 14 and sleeve 12 are preferablyconstructed from round tubing in this embodiment, but may also beconstructed from tubing having other geometric shapes such as, forexample, rectangular, oval, polygonal, combinations thereof and thelike. Although sleeve 12 may be made of a non-metallic material such asextruded polyethylene tubing, it is preferably metallic in order tocontribute significantly to the bending stiffness of tube assembly 10.In this embodiment, tube assembly 10 is relatively long and thin (forexample, fits through a 5 mm trocar) to enable the operator to useinstrument 8 for endoscopic vessel harvesting as will be described.

[0046] Closing tube 14 is further seen to have a tab 26 formed intoupper surface 22, which engages and opens upper jaw 42, as will bedescribed for FIG. 9.

[0047] Still referring to FIGS. 2 and 3, upper jaw 42 is seen to have aplurality of upper teeth 58, and lower jaw 44 is seen to have aplurality of lower teeth 56, thus defining a tissue grasping region 57.Upper jaw 42 also includes an upper channel 54, and lower jaw 44includes a lower channel 52, for the longitudinal movement of a cuttingelement 70 (see FIG. 4) partially contained inside of lower channel 52.A left fin 64 and a right fin 65 extend from lower jaw 44 to preventcutting element 70 from cutting tissue when upper jaw 42 is in the openposition. Upper jaw 42 further includes a blunt, upper tip 48 (alsocalled a distal tip), and lower jaw 44 has a blunt, lower tip 46 (alsocalled a distal tip). Upper tip 48 and lower tip 46 help the operator tofunnel tissue into tissue grasping region 57. When upper jaw 42 is inthe closed position, upper tip 48 and lower tip 46 form a V-shaped,dissecting tip 50 as shown in FIG. 3, which is useful for separatingtissue layers as will be described. Upper arm 30 of closing tube 14slides on a top surface 62 of upper jaw 42. Lower arm 28 of closing tube14 slides on a bottom surface 60 of lower jaw 44. When lower jaw 42 isin the closed position as shown in FIG. 3, top surface 62 and bottomsurface 60 are almost completely covered by closing tube 14. Tissueclamped between upper jaw 42 and lower jaw 44 extends laterally out ofleft slot 32 and right slot 33 (hidden) of closing tube 14, contacting aleft lower edge 34 and a right lower edge 35 (see FIG. 4). A left flange66 of upper jaw 42 separates tissue from a left upper edge 36 of upperarm 30. A right flange 67 (hidden) of upper jaw 42 separates tissue froma right upper edge 37 (hidden) of upper arm 30.

[0048] Now referring to FIG. 4, an exploded, isometric view of thedistal portion of tube assembly 10 is shown. Upper jaw 42 is seen tohave a distal portion 55 and a proximal portion 53 joined together at ahinge 49. Hinge 49 is sometimes referred to as a “living hinge” since itis a thin, flexible area of the injection molded, upper jaw 42. Upperjaw 42 also includes a cam follower 47 located near hinge 49, and a lip43 located on top surface 62. Lower jaw 44 includes a distal portion 59and a proximal portion 51 joined together at a cam 45. Cam follower 47of upper jaw 42 rides against cam 45 of lower jaw 44.

[0049] As seen in FIG. 4, cutting element 70 comprises a proximalportion 80 (partially shown), a distal portion 78, joined together at anoffset 84. Proximal portion 80 comprises a longitudinal element 76 andis attached to second actuator 102 shown in FIG. 1. Distal portion 78and proximal portion 80 may be constructed from one piece of metal, ormay be separate metallic elements joined together, for example, by aweld, mechanical connectors, rivets, pins, etc., and the like. Distalportion 78 is seen to have on the distal end a first blade 72 forcutting in the proximal direction and an opposed second blade 74 forcutting in the distal direction. The blades may be made as part of thedistal portion 78 or mounted thereto by conventional methods such aswelding, rivets, mechanical fasteners, etc. Lower jaw 44 containscutting element 70 in lower channel 52 so that edge 82 of cuttingelement 70 is approximately flush with lower teeth 56. Proximal portion80 of cutting element 70 is slideably contained in a right channel 95 ofa right retainer 91, and in a left channel 96 (hidden) of a leftretainer 90. Left and right retainers, 90 and 91, are also referred totogether as a shaft having a proximal and a distal end. Closing tube 14slides freely over left retainer 90 and right retainer 91, which aremounted to handle assembly 100 of FIG. 1. Right retainer 91 and leftretainer 90 are made from an electrically non-conductive material suchas plastic, for example, in order to electrically isolate cuttingelement 70 from closing tube 14. As a secondary electrical barrier,cutting element 70 may also be coated as desired with an insulativematerial. An example of a suitable coating for cutting element 70 is athin sufficiently effective (for example, about 0.005 mm), vacuumdeposited polymer well known in the art as parylene-n (also referred toas parylene), which is based on a high purity raw material calleddi-paraxylylene. Edge 82 of distal portion 78 of cutting element 70functions as an electrode surface and comes into contact with tissueheld between upper jaw 42 and lower jaw 44. Edge 82 (also referred to asa second electrode surface) is not coated with parylene-n or any otherinsulating material, and is a conductive surface.

[0050] Still referring to FIG. 4, right retainer 91 is seen to include aright hook 93 extending distally from the distal end thereof forattachment to a right hook 99 extending proximally from proximal section51 of lower jaw 44. Left retainer 90 includes a left hook 92 forengagement with a left hook 98 extending proximally from the proximalsection 51 lower jaw 44. As a result, lower jaw 44 is stationaryrelative to cutting element 70 and closing tube 14. The operatoractuates second actuator 102 to move cutting element 70 in eitherlongitudinal direction, and actuates first actuator 104 to move closingtube 104 in either longitudinal direction. Upper jaw 42 moves a shortdistance during opening and closing in the longitudinal directions dueto operational engagement with closing tube 14, as will be described.

[0051] Sleeve 12 fits concentrically over closing tube 14 andstrengthens tube assembly 10 to resist bending as described earlier, andmay be slidably mounted or fixedly mounted. Sleeve 12 also separatesclosing tube 14 from external structures rubbing against it that mayimpede its movement, such as tissue layers or a trocar seal if used witha trocar.

[0052]FIG. 5 is a cross-sectional view of the distal end of tubeassembly 10 of FIG. 3, taken along View Lines 5-5. Left lower edge 34(also referred to as a first conducting surface) and right lower edge 35(also referred to as a second conducting surface) of lower arm 28 ofclosing tube 14 (also referred to as a first electrode) have a firstpolarity, for example, shown as positive. Spaced midway between left andright lower edges, 34 and 35, is edge 82 of cutting element 70 containedin lower channel 52 of lower jaw 44. Edge 82 has a second, oppositepolarity, for example, shown as negative. Edge 82 is laterally offsetand electrical isolated from left and right lower edges, 34 and 35.Therefore, edge 82 cannot electrically short to left and right loweredges, 34 and 35, if there is no tissue clamped between upper jaw 42 andlower jaw 44. However, bipolar electrosurgical current flows betweenedge 82 and left lower edge 34 through tissue clamped in a leftcompression zone 88 and bipolar electrosurgical current flows betweenedge 82 and right lower edge 35 through tissue clamped in a rightcompression zone 89. Tissue is coagulated simultaneously in both leftcompression zone 88 and right compression zone 89. Once this tissue iscoagulated, tissue resistivity is increased and electrical conductivityis decreased. As a result, even though the operator may continue tosupply bipolar electrosurgical energy to instrument 8 (by depressing thefoot pedal control for the electrosurgical energy generator 6 of FIG.1), it is believed that effectively no additional coagulation of tissuetakes place. More significantly, there is no electrical pathway outsideof the clamped jaws, 42 and 44. Therefore, there is effectively nolateral thermal spread and coagulation of tissue outside of the jaws, 42and 44. Left upper edge 36 of closing tube 14 is electrically insulatedfrom clamped tissue by left flange 66 of upper jaw 42. Right upper edge37 of upper arm 30 of closing tube 14 is electrically insulated fromclamped tissue by right flange 67 of upper jaw 42. First and secondblades, 72 and 74, of cutting element 70 (see FIG. 4) extend into upperchannel 54, to cut tissue contained between compression zones 88 and 89.Upper channel 54 also serves as a vent for vapor to escape from upperjaw 42 during the application of RF energy.

[0053] As seen in FIG. 5, closing tube 14 has a substantiallyrectangular cross-section formed by upper surface 22, lower surface 23,left surface 20, and right surface 21. The upper and lower surfaces 22and 23 are seen to have a slightly curved configuration in a preferredembodiment. The rectangular cross-sectional configuration is believed tohave several advantages over, for example, a circular cross-sectionalconfiguration: the rectangular cross-sectional configuration allowsupper arm 30 and lower arm 28 to be stiffer so that deflection of upperarm 30 and lower arm 28 is minimized when tissue is clamped betweenupper jaw 42 and lower jaw 44; the rectangular cross-sectionalconfiguration allows better visualization of tissue structures on eachside of closing tube 14; the rectangular cross-sectional configurationhas a smaller footprint on the clamped tissue and allows a higherpressure to be applied to tissue for a given closing force applied, thusaiding in the formation of a hemostatic weld of the tissue.

[0054] The closing tube 14 is multifunctional in that it moves upper jaw42 between the open and closed positions, and it also serves as anelectrical conductor, with left and right lower edges, 34 and 35, beingused as outer electrodes of the same polarity. Similarly, cuttingelement 70 is multifunctional in that it not only cuts tissue heldbetween upper jaw 42 and lower jaw 44, but edge 82 of cutting element 70serves as an electrode having opposite polarity of closing tube 14. Bymaking closing tube 14 and cutting element 70 electrically activecomponents, it is not necessary to provide separate, spaced apart,bipolar electrodes in lower jaw 44. Consequently, the overall width oflower jaw 44 is significantly smaller than would be if separateelectrodes of opposite polarity were mounted in lower jaw 44. Thisenables the aforementioned benefits of a smaller footprint on thetissue. In addition, the number of components and the overall cost tomanufacture the instrument is reduced by the multifunctionality ofclosing tube 14 and cutting element 70.

[0055] Because instrument 8 incorporates offset electrodes technologyand the tissue reaches a high coagulation temperature only very briefly,tissue does not char or burn as may occur when using conventionalbipolar instruments. Nevertheless, a small amount of sticking of tissueto electrode surfaces in instrument 8 may still occur. In instrument 8,closing tube 14 moves longitudinally (i.e., proximally or distally) foreach time upper jaw 42 is opened or closed, thus causing the activeelectrical surfaces, right lower edge 35 and left lower edge 34, to moverelative to the stationary tissue held between upper jaw 42 and lowerjaw 44. This allows any tissue that may be adhering to right and loweredges, 34 and 35, after the application of energy and the coagulation oftissue, to break free. Similarly, each time the operator actuatescutting element 70 in either the proximal or distal direction, theelectrically active surface, edge 82 of cutting element 70, breaks freefrom adhering tissue. All electrically active surfaces in instrument 8are wiped against the tissue clamped for each cycle of operation(clamp/coagulate/cut/open), thus helping to keep those surfaces cleanand electrically conductive. In addition, when the operator opens upperjaw 42, the ends of the treated tissue are more likely to fall freelyfrom the jaws than if using conventional bipolar devices, and it is notnecessary to excessively manipulate instrument 8 to remove the tissue.

[0056]FIG. 6 is an exploded, isometric view of handle assembly 100,which preferably has an “in-line” style (as opposed to pistol-grip,etc.) in this embodiment, but is not restricted to this style. A righthandle shell 108 includes a plurality of bosses 160 for assembly to amatching number of gripper pins 161 on left handle shell 110. Right andleft handle shells, 108 and 110, are preferably injection molded from arigid, conventional biocompatible plastic such as polycarbonate and thelike. The shells 108 and 110 support the following components: firstactuator 104, second actuator 102, power cord 106, a divider 112, abidirectional spring 114, and a sequencing lever 116 (also referred toas a sequencing element or operational sequencing element).

[0057] As described for FIG. 1, first actuator 104 is slidably mountedin handle assembly 100 and controls the longitudinal movement of closingtube 14 for opening and closing upper jaw 42 (FIG. 2). When the operatormoves first actuator 104 distally from an open position to a distalclosed position, upper jaw 42 closes. When the operator moves firstactuator 104 proximally from the closed position to the open position,upper jaw 42 opens. First actuator 104 does not have a return spring orany other means for providing a biasing force to either the extended oropen position in this preferred embodiment, although it is possible andwithin the scope of this invention to do so.

[0058] Second actuator 102 controls the longitudinal movement of cuttingelement 70. When the operator moves second actuator 102 in the proximaldirection from a central position to a proximal position, first blade 72(FIG. 4) of cutting element 70 moves proximally and cuts through tissueclamped between upper jaw 42 and lower jaw 44 within tissue graspingregion 57 (FIG. 2). When the operator releases second actuator 102, itmoves from the proximal position back to the central position due to thebiasing force provided by bidirectional spring 114 (preferably a helicalcoil spring). As cutting element 70 moves distally from the proximalposition to the central position, second blade 74 (FIG. 4) of cuttingelement 70 cuts a second time through tissue clamped between upper jaw42 and lower jaw 44. When the operator moves second actuator 104 in thedistal direction from the central position to a distal position, cuttingelement 70 extends distally so that second blade 74 (FIG. 4) is exposedto tissue adjacent to dissecting tip 50, allowing the operator toseparate tissue layers and cut through tissue distally adjacent todissecting tip 50 as the operator advances instrument 8 in the distaldirection. When the operator releases second actuator 102, cuttingelement 70 moves proximally and again returns to the central positiondue to the biasing force provided by bidirectional spring 114. A biasingforce is provided for cutting element 70 in this embodiment so thatfirst and second cutting blades, 72 and 74, are safely contained betweenleft and right fins, 64 and 65, of lower jaw 44 when the operator is notactuating second actuator 102. In another embodiment of the presentinvention, bidirectional spring 114 may be eliminated so that movementof the cutting element 14 is possible only when the operator movessecond actuator 104.

[0059] Still referring to FIG. 6, second actuator 102 is seen to have aframe 103 that supports bidirectional spring 114, which is a helicalcoil wire compression spring in a preferred embodiment. If desired,other types of conventional springs may be used such as leaf springs,etc. A rail 132 on frame 103 of second actuator 102 rides inside of aright track 130 of right handle shell 108, so that bidirectional spring114 is trapped between a first stop 126 and a second stop 128 of righthandle shell 108. Second actuator 102 includes a mount member 136 havinga projection 137 for insertion into and engagement with a notch 154 oncutting element 70, so that longitudinal translation of second actuator104 causes an equal longitudinal translation of cutting element 70 inthe same direction. First actuator 104 is seen to have a bar slider 163,which rides on a left track 131 (hidden) on the inside of left handleshell 110. First actuator 104 also has a closing block 164 that containsa pair of slots 165 (hidden) for receiving a pair of tabs 172 extendingradially on the proximal end of closing tube 14, so that longitudinaltranslation of first actuator 102 causes an equal longitudinaltranslation of closing tube 14 in the same direction. Closing block 164is supported and guided also by a right shelf 162 in right handle shell108 and a left shelf 155 (hidden) in left handle shell 110. Firstactuator 104 and second actuator 102 are separated by divider 112 havinga top fin 142 to help prevent the operator from actuating first andsecond actuators, 104 and 102, at the same time. Divider 112 alsoprovides a tactile, positional reference for the operator to know therelative positions of first and second actuators, 104 and 102, withoutlooking at them. A first tab 138 and a second tab 140 extending offopposite ends of divider 112 mount divider 112 to a first support 146and a second support 148, respectively, of right handle shell 108. Ayoke 144 on divider 112 mounts onto a right retaining fin 150 of righthandle shell 108 and a similar, left retaining fin 151 (hidden) on theinside of left handle shell 110. First actuator 104, second actuator102, and divider 112 are preferably injection molded from a rigid,biocompatible plastic such as polycarbonate, although many otherconentional materials may also be used.

[0060] Still referring to FIG. 6, an optional, although preferred,sequencing lever 116 (also referred to as a sequencing element) ensuresthe proper sequence of operation of first and second actuators, 104 and102. More specifically, sequencing lever 116 locks out second actuator102 from moving to the proximal position (moving cutting element 70 tothe proximal position) unless first actuator 104 is at the closedposition (for when upper jaw 42 is closed and tissue is clamped). Whentissue has been clamped for a period of time and electrosurgicallycoagulated, the tissue becomes less elastic and clamping force relaxes.To severe the coagulated tissue hemostatically, however, it is importantthat the coagulated tissue continue to be held firmly between upper andlower jaws, 104 and 102, so that cutting element 70 cuts through themiddle of the coagulated tissue. This leaves an equal margin ofcoagulated tissue on each of the severed ends of the tissue so that thetransection is hemostatic. Sequencing lever 116 also prevents first andsecond blades, 72 and 74, from being exposed to tissue in tissuegrasping region 57 (FIG. 2) between upper and lower jaws, 42 and 44,while the operator positions instrument 8 prior to clamping, thuspreventing inadvertent cutting of the tissue. Sequencing lever 116 alsoprevents first actuator 104 from moving from the closed position to theopen position (to open upper jaw 42) unless second actuator 102 issafely in the distal or central positions and first and second blades,72 and 74, are not in tissue clamping region 57. Sequencing lever 116 ispreferably made of stainless steel, although it may be injection moldedfrom a rigid, high strength plastic or other conventional materials.Sequencing lever 116 has a hole 168 that mounts pivotably onto post 166of right handle shell 108, and a slot 170 for operational engagementwith a first pin 134 extending off of frame 103 of second actuator 102.

[0061]FIG. 6 depicts a portion of power cord 106 having a strainreliever 174 that inserts between a pair of bosses 160 in right handleshell 108. Power cord 106 also includes an electrically insulated, firstconductor 11 8 terminating with a first connector 122 for electricalattachment to cutting element 70, and an electrically insulated, secondconductor 120 terminating with a second connector 124 for electricalattachment to closing tube 14. First and second connectors, 122 and 124,are shown in this embodiment to be configured for quick assembly,although various other types of connectors well known in the art orsoldering and other conventional mounting techniques may be used in thisapplication. The conductors are made from conventional conductingmaterials including copper wire, aluminum wire and the like andequivalents thereof.

[0062] Still referring to FIG. 6, it can be seen that handle assembly100 retains tube assembly 10 as follows: left and right retainers, 90and 91, have a pair of opposing recesses 152 for staking to left andright retaining fins, 151 (hidden) and 150. Sleeve 12 has a pair ofopposing slits 156 (one is hidden) for retention in a right cradle 158of right handle shell 108 and a left cradle 157 (hidden) of left handleshell 110. A holder 159 supports sleeve 12.

[0063] Now referring to FIG. 7, a side view of handle assembly 100without left shell 110 reveals the orientation of sequencing lever 116for when first actuator 104, attached to closing tube 14, is in the openposition and second actuator 102 (substantially hidden by fin 142) is inthe central position. First pin 134, which extends from frame 103 ofsecond actuator 104 rests in slot 170 of sequencing lever 116. Closingblock 164 of first actuator 104 prevents rotation of sequencing lever116 about post 166, thereby causing slot 170 to be inclined relative tothe longitudinal axis of handle assembly 100, and preventing movement inthe proximal (right) direction of second actuator 102. As FIG. 7 shows,a lever end 117 cannot move in the clockwise direction until a closingblock corner 169 is distal to it, thus preventing movement of secondactuator 104 in the distal direction. Bi-directional spring 114 isslightly compressed within frame 103, but does not exert a biasing forceon second actuator 102 in either longitudinal direction.

[0064]FIG. 8 is a top view of handle assembly 100 showing the positionsof first actuator 104 and second actuator 102 (separated by fin 142)corresponding with FIG. 7.

[0065]FIG. 9 is a cross-sectional view of the distal portion of tubeassembly 10, and corresponds with FIGS. 7 and 8. Closing tube 14 is inthe open position so that tab 26 engages a lip 43 of upper jaw 42,causing a follower 47 of upper jaw 42 to ride up on a cam 45 of lowerjaw 44, thus causing upper jaw 42 to flex at a hinge 49 of upper jaw 42to the open position. Cutting element 70 is in the central position withfirst blade 72 and second blade 74 protected by left fin 64 (removed inthis view) and right fin 65. When upper jaw 42 closes against lower jaw44, cam 45 and left and right fins, 64 and 65, contain tissue to beclamped in tissue grasping region 57, ensuring that tissue to be treateddoes not squeeze out the distal end of the upper and lower jaws, 42 and44, as may occur in other surgical grasping instruments. The wipingaction of follower 47 against cam 45 also ensures that tissue is notpinched in between upper and lower jaws, 42 and 44, such as may occur inother surgical grasping instruments.

[0066]FIG. 10 is a side view of handle assembly 100 with left shell 110removed to reveal the position of sequencing lever 116 for when firstactuator 104 is in the closed position and second actuator 102(substantially hidden by fin 142) is in the central position. Closingblock corner 169 of closing block 164 is distal to lever end 117, thusallowing rotation of sequencing lever 116 about post 166, and proximaltranslation of second actuator 102. As first pin 134 extending off frame103 translates proximally, slot 170 moves from the steeply inclinedorientation shown in FIG. 10 to a less inclined position as shown inFIG. 13. Bi-directional spring 114 is in the same configuration for FIG.10 as for FIG. 7, and is not providing a biasing force in eitherlongitudinal direction to second actuator 104.

[0067]FIG. 11 corresponds with FIG. 10 and shows a top view of handleassembly 100 for when first actuator 104 is in the closed position andsecond actuator 102 is in the central position, with fin 142 betweenfirst actuator 104 and second actuator 102.

[0068]FIG. 12 is a sectional view of the distal portion of tube assembly10 corresponding with FIGS. 10 and 11. Upper jaw 42 is in the closedposition and tab 26 of closing tube 14 is separated from lip 43 of upperjaw 42. Follower 47 of upper jaw 42 abuts cam 45 of lower jaw 44 so thatupper jaw 42 fits tightly against lower jaw 44 with very minimal airgaps there between. This ensures that tissue may be securely clampedduring coagulation and cutting, and provides an additional electricalbarrier between cutting element 70 and closing tube 14. First blade 72and second blade 74 are in the central position and safely separatedfrom tissue that may be clamped between upper jaw 42 and lower jaw 44.Dissecting tip 50 may be used in this configuration as a blunt dissectorand tissue layer separator without cutting.

[0069]FIG. 13 is a side view of handle assembly 100 with left shell 110removed to reveal the position of sequencing lever 116 for when firstactuator 104 is in the closed position and second actuator 102 is in theproximal position. Fin 142 provides a tactile reference for the operatorto feel the change of position for first and second actuators, 104 and102. Closing block corner 169 of closing block 164 is distal to leverend 117 so that sequencing lever 116 rotates about post 166 when firstpin 134 translates proximally within slot 170. Bi-directional spring 114is compressed between frame 103 of second actuator 102 and second stop128 of handle shell 108, thus providing a biasing force in the distaldirection (and urging second actuator 104 to move from the proximalposition to the central position.)

[0070]FIG. 14 is a top view of handle assembly 100 corresponding withFIG. 13 for when first actuator 104 is in the closed position and secondactuator 102 is in the proximal position. Fin 142 separates first andsecond actuators, 104 and 102.

[0071]FIG. 15 is a sectional view of the distal portion of tube assembly10 corresponding to FIGS. 13 and 14. Upper jaw 42 is in the closedposition with closing tube 14 substantially covering upper jaw 42 andlower jaw 44. Cutting element 70 is shown in the proximal position withfirst blade 72 having made a first cut through tissue that may have beenclamped between upper and lower jaws, 42 and 44. Second blade 74 ispositioned to make a second pass through the tissue upon release ofsecond actuator 104 (FIG. 13).

[0072]FIG. 16 is a side view of handle assembly 100 with left handleshell 110 removed and shows the position of sequencing lever 116 forwhen first actuator 104 is in the closed position and second actuator102 (substantially hidden by fin 142) is in the distal position. Closingblock corner 169 of closing block 164 is again distal to lever end 117,although this is not necessary for pin 134 to move in the distaldirection inside of slot 170 of sequencing lever 116. Bi-directionalspring 114 is compressed between first stop 126 of right handle shell108 and frame 103 of second actuator 104, thus providing a biasing forceto second actuator 104 in the proximal direction.

[0073]FIG. 17 is a top view of handle assembly 100 corresponding withFIG. 16, and shows first actuator 104 in the closed position. Fin 142separates first actuator 104 from second actuator 102, which is in thedistal position. The operator must hold second actuator 104 in thedistal position due to the biasing force, which bidirectional spring 114provides.

[0074]FIG. 18 is a sectional view of the distal portion of tube assembly10, corresponding with FIGS. 16 and 17. Closing tube 14 surrounds upperjaw 42 and lower jaw 44 in the closed position. Cutting element 70 is inthe distal position so that second blade 74 extends partially into theV-shape opening of dissecting tip 50 and is able to sever tissue thatwould be distally adjacent to dissecting tip 50. Second blade 72 isstill protected within upper jaw 42 and lower jaw 44.

[0075]FIG. 19 is a isometric view of instrument 8 being used for asurgical procedure in combination with a surgical retractor 200 forendoscopically harvesting a vessel 224 from a surgical patient 220 foruse in a coronary artery bypass graft (CABG) surgical procedure.Retractor 200 and its method of use are disclosed in U.S. Pat. Nos.5,928,138 and 5,928,135 and are hereby incorporated herein forreference. Retractor 200 comprises a grip 204 attached to the proximalend of an endoscopic shaft 208, which may be inserted into an incision226. A spoon element 206 is attached to the distal end of endoscopicshaft 208. The operator manipulates retractor 200 to advance a spoonshaped, working head 206 along vessel 224, separating tissue from vessel224 and providing a working space for accessing and visualizing vessel224 and a plurality of side branches 222. A port 202 provides access foran endoscope (not shown) for visualization within working head 206. Anozzle 210 may connect to a low pressure, carbon dioxide gas source forclearing away vapor and smoke from within the working space insideworking head 206. Tube assembly 10 of instrument 8 inserts throughincision 226 underneath shaft 208 of retractor 200. Tube assembly 10could also be inserted through a port in an endoscope or retractor orendoscopic vein harvesting instrument. The operator manipulatesinstrument 8 within the working space inside working head 206 todissect, clamp, coagulate, and cut tissue as described for FIGS. 7-18.In particular, side branches 222 are coagulated and cut without damagingharvested vessel 224. The length of tube assembly 10 may vary, butpreferably is long enough for handle assembly 100 to be proximal to theendoscope inserts into port 202 while tube assembly 10 is inserted farenough into patient 220 to access the working space within working head206. Instrument 8 may be used with other conventional retractors andvein harvesting instruments.

[0076] Instrument 8 is especially suited for vessel harvesting asdescribed for FIG. 19, but is not limited to only this surgicalprocedure. Instrument 8 may also be used to dissect, clamp, coagulate,and cut tissues during numerous other types of endoscopic and opensurgical procedures. Instrument 8, as described in the presentembodiment, is intended for single patient use. Instrument 8 may beconstructed, however, from materials and using techniques, allowingresterilization and reuse on more than one surgical patient.

[0077] Although this invention has been shown and described with respectto detailed embodiments thereof, it will be understood by those skilledin the art that various changes in form and detail thereof may be madewithout departing from the spirit and scope of the claimed invention.

1. A surgical instrument comprising: a) a handle having a proximal end,a distal end, a top and a bottom; b) a shaft having a distal end, aproximal end, and a longitudinal axis, said proximal end of the shaftmounted to the distal end of the handle; c) a closing tube having adistal end, a proximal end, and a longitudinal axis, said closing tubeslidably mounted coaxially to said shaft; d) a first jaw extending fromsaid distal end of the closing tube, the first jaw having a distal end,a proximal end, and a longitudinal axis, the first jaw having a hingebetween the distal and proximal ends of the first jaw, wherein saiddistal end is rotatable about the hinge toward and away from thelongitudinal axis of the first jaw; e) a second opposed jaw extendingfrom the distal end of the closing tube, the second jaw mounted to thedistal end of the shaft and retaining the first jaw inside of distal endof the closing tube, the second jaw having a distal end, a proximal end,and a longitudinal axis, wherein the said closing tube slideably fitsover the first and second jaws so that a tissue grasping region of thefirst and second jaws is distal to the distal end of said closing tube,wherein the closing tube movable relative to the first and second jawsbetween an open and a closed position; f) a cam located on the secondjaw and operationally engaged with a follower member on the first jaw,such that when said closing tube moves from the closed position to theopen position the closing tube operationally engages the first jaw andmoves the first jaw relative to the lower jaw in the proximal directionso that the follower member of the first jaw rides up on the cam on thelower jaw and causes the hinge to flex and the distal end of the firstjaw to move away from the second jaw, and when the closing tube movesfrom the open position to the closed position the closing tubeoperationally engages the first jaw and moves the first jaw relative tothe second jaw in the distal direction so that the follower member ridesdown on the cam on the second jaw and causes the hinge to flex and thedistal end of the first jaw to move towards the second jaw; and, g) anactuator mounted to the handle for moving the closing tube, wherein theproximal end of the closing tube is mounted to the actuator.
 2. Thesurgical instrument of claim 1 wherein the jaw comprises a flexiblematerial.
 3. The surgical instrument of claim 1 wherein the hingecomprises a living hinge.
 4. The surgical instrument of claim 1 whereinthe first and second jaws comprise an electrically non-conductivematerial.
 5. The surgical instrument of claim 1 wherein the first jawhas an unconstrained configuration in the open position.
 6. The surgicalinstrument of claim 1 wherein said upper jaw has an unconstrainedconfiguration in said closed position.
 7. The surgical instrument ofclaim 1 further comprising a plurality of teeth extending from at leastone of the first and second jaws for engaging tissue within the tissuegrasping region.
 8. The surgical instrument of claim 1 wherin the handleis hollow and has a cavity therein.
 9. The instrument of claim 8,wherein the actuator is slidably mounted to the handle and has a lowermember which extends into the cavity, and wherein the proximal end ofthe tube is mounted to the lower member.
 10. A method of grasping tissuecomprising the steps of: I. providing a surgical instrument, thesurgical instrument comprising: a handle having a proximal end, a distalend, a top and a bottom; a shaft having a distal end, a proximal end,and a longitudinal axis, said proximal end of the shaft mounted to thedistal end of the handle; a closing tube having a distal end, a proximalend, and a longitudinal axis, said closing tube slidably mountedcoaxially to said shaft; a first jaw extending from said distal end ofthe closing tube, the first jaw having a distal end, a proximal end, anda longitudinal axis, the first jaw having a hinge between the distal andproximal ends of the first jaw, wherein said distal end is rotatableabout the hinge toward and away from the longitudinal axis of the firstjaw; a second opposed jaw extending from the distal end of the closingtube, the second jaw mounted to the distal end of the shaft andretaining the first jaw inside of distal end of the closing tube, thesecond jaw having a distal end, a proximal end, and a longitudinal axis,wherein the said closing tube slideably fits over the first and secondjaws so that a tissue grasping region of the first and second jaws isdistal to the distal end of said closing tube, wherein the closing tubemovable relative to the first and second jaws between an open and aclosed position; a cam located on the second jaw and operationallyengaged with a follower member on the first jaw, such that when saidclosing tube moves from the closed position to the open position theclosing tube operationally engages the first jaw and moves the first jawrelative to the lower jaw in the proximal direction so that the followermember of the first jaw rides up on the cam on the lower jaw and causesthe hinge to flex and the distal end of the first jaw to move away fromthe second jaw, and when the closing tube moves from the open positionto the closed position the closing tube operationally engages the firstjaw and moves the first jaw relative to the second jaw in the distaldirection so that the follower member rides down on the cam on thesecond jaw and causes the hinge to flex and the distal end of the firstjaw to move towards the second jaw; and, an actuator mounted to thehandle for moving the closing tube, wherein the proximal end of theclosing tube is mounted to the actuator; II. moving the tube to the openposition and positioning tissue between the jaws; and, III. moving thetube to the closed position and engaging the tissue in the tissuegrasping region.